tsp0054

I am looking for some good sources to purchase Arduino accessories (LEDs, Resistors, Switches) items of this sort. I am familiar with just Sparkfun however I want to know where you get your stuff and why. Thanks in advance!!

Yup. Blatant violation of the trademark. The truly sad part is that they obviously modified the design. Guess it was too much effort to remove the logo. Either that or they couldn't resist the temptation to purloin someone else's reputation.

Terry has designed broadcast stations, recording studios, broadcast equipment, intelligent machines and special computer languages for IBM, and has worked as a broadcast journalist covering elections, fires, riots and Woodstock.
He has taught electronics

http://www.youdoitelectronics.com/ -- In Needham, MA. For me, it is a bit of a trek, so I can't do it on the spur of the moment. In addition to a lot more parts than Electronics Plus, You-do-it has recently discovered Arduino compatibles, and carries various Osepp and Sparkfun kits.

http://www.radioshack.com/home/index.jsp -- They are everywhere, but if you need just a few parts and don't need hand holding by the staff, their prices for one off components, aren't too bad considering typical shipping charges. You typically want to go to the back of the store, and browse through the several filing cabinets that they have of various components. RS does sell actual Arduino products, though the prices can be higher than you find elsewhere.

Now, on to the mail order sites you asked about. In general, I prefer to deal with sites that have USA distributors so that I get the stuff in a few days, rather than a couple weeks.

http://www.dipmicro.com/store/index.php -- I found this through another forum member, and the prices are great. While they are primarily Canadian, they do mail from Niagara Falls, NY so you don't get customs. I was impressed that each of the parts I got were labeled in plastic bags, as I bought my original UNO from a vendor that just threw all parts in a single plastic bag.

http://www.adafruit.com/ -- I originally avoided Adafruit and Sparkfun since most of their boards needed soldering. While I can solder now, I still prefer for things like shields to buy ones that are pre-soldered. I tend to go here for more unique designs, and also because they have a lot of tutorials that the creator (Limor Fried) or her staff wrote themselves. Adafruit is based in New York city.

http://www.sparkfun.com -- You already know about this one. However, at times, I get the sense that they think they are more cool than they are, and it is a slight turn off. They are based in Colorado. While I often look at sparkfun, I tend to prefer Adafruit over Sparkfun, and I haven't ordered from them (I do have a few designs that I might get some day).

http://www.robotshop.com/store -- While their focus is robotics, they do carry a lot of stuff for non-robotic microprocessor projects as well if you go to the robot parts sublink. They carry a lot of various shields, sensors, etc. Robotshop is world wide, but their US operations is in Vermont.

http://www.pololu.com/ -- This is another robot venture that also deals with basic electronics and shields, kits, etc. They are based in Los Vegas, Nevada.

http://yourduino.com/ -- This company is almost entirely Arduino based. One of the owners (Terry King) posts often in these forums, and has good tutorials on his site that he wrote. I value that in a site. Yourduino, ships from China, so you have to factor in the longer delivery times.

These places build a lot of shields, sensors, etc. Often times you can find the parts at distributors that are in your country, but for datasheets and tutorials, you need to go back to the company that built the item. They also do mail order directly:

http://www.thinkgeek.com -- Thinkgeek. Like Sparkfun, a little too impressed with themselves, but still fun items. I do find the markup on their electronic items to be higher, so if you can find the stuff elesewhere, you likely will get better prices.

Edit-2:Here are some projects that started out on kickstarter that built a specific part. Some are now shipping to general customers and you can order the gadget directly. Some are still trying to satisfy the original kickstarter orders, and you won't be able to get the item, until the original orders are done:

BillO

http://www.dipmicro.com/store/index.php -- I found this through another forum member, and the prices are great. While they are primarily Canadian, they do mail from Niagara Falls, NY so you don't get customs. I was impressed that each of the parts I got were labeled in plastic bags, as I bought my original UNO from a vendor that just threw all parts in a single plastic bag.

There should be no duty on electronics parts/sub-assemblies/PCBs/etc... coming into the US from Canada.

DirtBiker

You've got a lot of suggestions already, but I'd add www.aztecmcu.com. I've bought quite a bit off them of late. Their selection is not the greatest right now, but it does seem to be growing. What they do carry is very well priced and they have some unique stuff that works really well.

They are in Canada, but as BillO points out, that does not seem to make any difference. Never been charged duty and it does not seem to take any longer for shipments to arrive than from other vendors.